Conventionally, a long continuous film is surface-modified through ion implantation. In one mode of the technique, while the film is conveyed toward one direction, ions in a plasma are implanted into the target surface of the film, to thereby form a gas barrier layer on, for example, the surface of the film (see, for example, Patent Document 1).
Patent Document 1 discloses an ion implantation apparatus for carrying out ion implantation. The ion implantation apparatus disclosed in Patent Document 1 includes, in the vacuum chamber thereof, rollers such as an unwind roller, a wind-up roller, and a roller electrode, and gas introduction means. The roller electrode is connected to voltage application means.
In the above ion implantation apparatus, an ion implantation gas is fed to the chamber. When a voltage is applied to the roller electrode by the voltage application means, an electric field is provided between the roller electrode and the chamber wall serving as a ground, to thereby form a plasma. Through application of negative DC high-voltage pulse, ions generated by the plasma are drawn to the roller electrode, whereby the ions are implanted into the surface of the film wound on the roller electrode.